Central pontine myelinolysis following hyponatremia, demonstrated by computerized tomography

Too Aggressive Drop in Blood Pressure in a Hypertensive Male Leading to "Man-in-the-Barrel Syndrome"

Introduction

"Man-in-the-barrel syndrome" is a neurological phenotype with brachial diplegia, normal sensation, and preserved motor function of the lower limb. It has been described in various neuropathological conditions affecting the cerebral hemispheres, pons, upper spinal cord, and peripheral neurons. Severe hypotension leading to watershed infarctions leading to this phenotype has been reported. We describe the first case of "man-in-the-barrel syndrome" in a patient with a precipitous drop in blood pressure following oral antihypertensive medications. Case Presentation. A 75-year-old Sri Lankan male presented following a generalized tonic-clonic seizure to a tertiary care hospital. Upon recovery, he was noted to have severe brachia diplegia affecting shoulder movements with preserved hand muscle power and motor functions of the lower limb. The previous day, he was newly diagnosed with markedly elevated blood pressure without acute end organ involvement. Treatment with three antihypertensives had been initiated. Noncontrast CT of the brain revealed watershed infarctions affecting both cerebral hemispheres.

Conclusion

It is generally unwise to lower blood pressure very rapidly, as ischemic damage can occur in vascular beds that are habituated to high levels of blood pressure in the brain. Ischemic damage caused by rapid lowering of blood pressure may rarely result in "man-in-the-barrel syndrome" leading to severe functional disability.

“Man-in-the-barrel” syndrome as delayed manifestation of extrapontine and central pontine myelinolysis: Beneficial effect of intravenous immunoglobulin

"Man-in-the-barrel" syndrome has been rarely described following osmotic myelinolysis. We report a case of a 45-year-old woman admitted with septicemia and severe hyponatremia. She presented with a "man-in-the-barrel" syndrome which developed more than 10 days after rapid correction of the hyponatremia. There was radiological evidence of central pontine and extrapontine myelinolysis. Three days after completing a course of intravenous immunoglobulin therapy (0.4 g/kg body weight/day for 5 days) there was considerable improvement (Expanded Disability Status Scale score improved 30%). This case, reported for its peculiar mode of development, unusual presentation and challenging therapeutic response to intravenous immunoglobulin, highlights the enigmatic and unpredictable aspects of osmotic myelinolysis.

Cruciate paralysis or man-in-the-barrel syndrome? Report of a case of brachial diplegia

A patient who developed isolated brachial diplegia following cardiac surgery is described. The underlying cerebral lesion could not be localized using magnetic resonance imaging (MRI). Evoked potentials disclosed normal findings, while pathological latencies were seen on cortical magnetic stimulation. Their marked improvement over the following year was accompanied by almost complete clinical recovery. The preserved arm reflexes, together with the observed slow firing motor units in electromyography argued against bilateral lesions of the brachial plexus. We attribute the observed diplegia to a medullary lesion at the level of the pyramidal decussation, presumably caused by an intraoperative embolic occlusion of the anterior spinal artery. Cruciate paralysis and man-in-barrel-syndrome (MIBS) both are terms used to describe brachial diplegia; cruciate paralysis when caused by medullary lesions, MIBS when caused either by supratentorial or by medullary lesions. Exclusive use of the term MIBS for bilateral frontal lobe lesions, as in the original description, would provide more clarity in terminology.

Langerhans cell histiocytosis: diagnosis, natural history, management, and outcome

BACKGROUND

The objective of this descriptive analysis of a large cohort of patients with Langerhans cell histiocytosis (LCH) was to add to the understanding of the natural history, management, and outcome of this disease.

METHODS

Three hundred fourteen Mayo Clinic patients with histologically proven LCH were categorized into those patients with multisystem disease and those patients with single system disease. Clinical features, treatment, and outcome were determined from the case history notes and tumor registry correspondence. Treatment included chemotherapy, radiotherapy, and surgical excision. The end points were disease free survival, active disease, or death. The median time of follow-up was 4 years (range, 1 month to 47.5 years).

RESULTS

The age of the patients ranged from 2 months to 83 years. Of the 314 patients, there were 28 deaths. Multisystemic LCH was found in 96 patients, 25 of whom had continuing active disease after treatment. Isolated bone LCH lesions were observed in 114 of the 314 patients, 111 of whom (97%) achieved disease free survival after treatment. The most common sites of osseous LCH were the skull and proximal femur. Of the 87 patients with isolated pulmonary involvement, only 3 were nonsmokers. After treatment with corticosteroids (+/- cyclophosphamide or busulphan), 74 patients achieved disease free survival, but 10 patients died. Pituitary-thalamic axis LCH, characterized by diabetes insipidus, was found in 44 patients. After treatment, 30 of these patients had disease free survival, but all required long term hormone replacement with desmopressin acetate. Lymph node involvement was found in 21 patients, and mucocutaneous involvement was found in 77 patients.

CONCLUSIONS

Patients with isolated bone LCH lesions have the best prognosis compared with patients with LCH involvement of other systems. By contrast, 20% of patients with multisystem involvement have a progressive disease course despite treatment. The identification of prognostic indicators to facilitate appropriate treatment and long term follow-up surveillance is recommended.

Regressive dystonia and cerebellar ataxia: two unusual symptoms in central pontine myelinolysis

Two patients with central pontine myelinolysis who presented with dystonia are described. In one, it was associated with cerebellar ataxia which spontaneously improved. In the second, dystonia progressively disappeared 6 months later. In both cases magnetic resonance imaging (MRI) revealed characteristic pontine lesions. Extrapontine myelinolysis involving the putamen was also observed in one patient. Even when the basal ganglia seem to be spared on MRI, dystonia is probably due to their involvement by myelinolysis. Cerebellar ataxia may be related to peduncular or cerebellar lesions or both.

Osmotic demyelination syndrome following correction of hyponatremia: association with hypokalemia

The osmotic demyelination syndrome (ODS) is a neurologic complication associated with rapid correction of hyponatremia. A case is described in which the patient was found to have hypokalemia as well as hyponatremia prior to the development of ODS. The literature was reviewed for cases of ODS in which patients had hyponatremia (serum sodium < or = 126 mmol/L) at presentation followed by correction of the hyponatremia. Of the 74 cases in which serum sodium and serum potassium values were reported at the time of presentation, 66 patients (89%) had hypokalemia. In 20 of these cases, serial measurements of sodium and potassium were reported, and in no instance was the potassium level normalized prior to the time of most rapid correction of the serum sodium. Hypokalemia may predispose patients to develop osmotic demyelination following correction of hyponatremia. The etiology of this complication is unclear. In neurologically stable patients with severe hyponatremia, it may be beneficial to correct hypokalemia prior to correction of the serum sodium. This maneuver may further reduce the incidence of ODS.

Symptomatic hyponatraemia: can myelinolysis be prevented by treatment?

The treatment of hyponatraemia is controversial because of the risk of causing central or extrapontine myelinolysis (EPM). Rapid correction with hypertonic saline to a low normal sodium level has its proponents; others feel that slow correction to below normal sodium values is preventative. Most investigators feel that overcorrection should be avoided. It is not known whether the magnitude of serum sodium change is more important than the actual rate of correction. We present three patients with hyponatraemia ranging from 103 to 105 mmol/l who were corrected slowly with normal saline, corrected quickly with hypertonic saline, or rapidly overcorrected with hypertonic saline. All became comatose and died; all had EPM with or without central pontine myelinolysis (CPM). The rate of correction, the solution used, or the magnitude of correction did not seem to protect against demyelination. In a review of 67 reported CPM cases since 1983, no patients documented as having CPM or EPM by radiological studies or necropsy were treated with water restriction only. A group of 27 hyponatraemic patients treated only with water restriction and 35 with diuretic cessation alone did not develop CPM or EPM. This may be a reasonable approach to patients with symptomatic hyponatraemia and normal renal function.

Central pontine myelinolysis: report of two occurrences after cisplatin-containing chemotherapy for nasopharyngeal carcinoma

We report two patients with the classical clinical syndrome of central pontine myelinolysis following cisplatin based chemotherapy for nasopharyngeal carcinoma. The diagnosis was supported by typical features on magnetic resonance imaging. Rapid correction of hyponatraemia was the most likely cause. A short course of corticosteroids was tried in both patients. Although one patient experienced almost complete recovery, the other still suffered from residual motor deficit. The importance of careful monitoring of the rate of electrolyte correction is emphasized.

Management of severe hyponatremia: rapid or slow correction?

Case reports and the literature on the treatment of severe hyponatremia were reviewed. It appeared that the conflicting opinions with respect to the rate of correction of severe hyponatremia could be reduced to not differentiating between acute and chronic hyponatremia, to using different criteria for this distinction, and to differences in treatment strategy. After reviewing the available data in the literature, it is suggested that hyponatremia should be classified as acute whenever the rate of decrease of serum sodium exceeds 0.5 mmol/L/hour. If it is unknown at which rate the hyponatremia has developed, it can be assumed to be acute if within a short period of time (two to three days), large quantities of fluid are ingested orally or administered parenterally, especially hypotonic fluids in the presence of impaired water excretion. In other cases, chronic hyponatremia is probable. It is concluded that acute hyponatremia should be treated without delay and rapidly at a rate of at least 1 mmol/L/hour, to prevent severe neurologic damage or death. With respect to chronic hyponatremia, it appeared that severe neurologic complications almost exclusively occurred in patients who were treated with hypertonic or isotonic saline without the addition of furosemide or an osmotic diuretic agent, resulting in a (rapid) correction rate of 0.5 mmol/L/hour or more. In contrast, patients with severe chronic hyponatremia treated with furosemide and isotonic or hypertonic saline almost uniformly did well after rapid correction. Uneventful recovery is also the rule when severe chronic hyponatremia is corrected slowly, at a rate less than 0.5 mmol/L/hour. On pathophysiologic grounds, and bearing in mind that slow correction was used in the majority of reported patients in the literature with severe chronic hyponatremia who recovered without neurologic complications, this treatment modality is preferable. Whenever the available data do not permit a differentiation between acute or chronic hyponatremia, rapid correction has to be pursued by means of administration of hypertonic or isotonic saline together with furosemide.

[Central pontine myelinolysis following severe hyponatremia]

Central pontine myelinolysis is a process of demyelinisation with variable neurological symptoms related to the localization. Predisposing factors are alcoholism and malnutrition. Rapid correction of severe hyponatremia is suspected to be a primary cause for central pontine myelinolysis. We report a 43 year old chronic alcoholic and polytoxicomanic female patient, who was admitted comatose with a serum sodium level of 94 mmol/l, caused by a syndrome of inappropriate ADH secretion. After initial improvement under careful sodium correction, the patients neurologic condition degraded progressively and within 4 weeks she developed a "locked-in"-syndrome. Only then the suspected central pontine myelinolysis could be demonstrated in nuclear magnetic resonance and computer tomography. We presume that, although sodium correction was done relatively slowly in this patient, it probably contributed to her development of central pontine myelinolysis all the same. Due to this case we review the literature on correction of hyponatremia, which shows growing evidence that it should start early but be continued very slowly (rise in serum-Na: max. 0.6 mmol/l/h) and requires frequent laboratory controls.

Magnetic resonance imaging in central pontine myelinolysis

Magnetic resonance imaging (MRI) was performed in two patients in whom a clinical diagnosis of central pontine myelinolysis (CPM) had been made. MRI showed lesions in the pons in both cases about 2 years after the illness, at a time when the spastic quadriparesis and pseudobulbar palsy had recovered. The persisting abnormal signals in CPM are likely to be due to fibrillary gliosis. Persistence of lesions on MRI means that the diagnosis of CPM may be electively, after the acute illness has resolved.

[Central pontine myelosis. Morphology and forensic importance]

Central pontine myelinolysis (CPM) evidently occurs more frequently than had been assumed up to now owing to the cases that have been substantiated solely on the basis of pathological anatomy. Its genesis is still unclarified. Computed tomography and magnetic resonance methods allow detection of the foci while the affected person is still alive. They are clearly capable of regression and are not automatically accompanied by a poor prognosis. Since an iatrogenic factor (forced compensation of hyponatremia) is increasingly under discussion as the cause of CPM, the condition also has substantial significance from a forensic point of view. On the basis of a prospective study on CPM confirmed in 100 brains of alcoholics, as well as 4 further cases from the forensic autopsy material, it is shown that hyponatremia is not likely to be the sole triggering factor. The course of the condition in the cases investigated shows that the capacity for action may be preserved up to death (which has occurred for other reasons) in not very pronounced CPM. In questionable violent and other unclear deaths, CPM must also be considered a possible cause of death. The various hypotheses on its etiology in the extensive literature are compared with the findings in our own cases and discussed.

Autopsy validation of MRI in central pontine myelinolysis

In a fatal case of central pontine myelinolysis (CPM) a low field strength (0.08 Tesla) magnetic resonance image revealed reduction of image intensity in the pons with sparing of two central symmetrical areas in the ventral portion. The latter correlated with preservation of centrally located groups of longitudinal myelinated nerve fibres shown at autopsy. Although such sparing is well recognised in pathological studies of CPM it has never previously been demonstrated in life.

MR demonstration of mesencephalic lesions in osmotic demyelination syndrome (central pontine myelinolysis)

A case of CPM/ODS with mesencephalic involvement is presented. The lesions were non-enhancing on CT and were homogeneous and well-defined on MR with prolonged T1- and T2-relaxation times. MR is recommended for imaging the pontomesencephalic demyelinating lesions associated with this disease.

Central pontine myelinolysis: diagnosis by computed tomography, magnetic resonance and evoked potentials

The intravital diagnosis of central pontine myelinolysis has become possible with the introduction of computed tomography and magnetic resonance into neurological diagnostics. These tools are of special value when neurological signs of a ventral pontine lesion are lacking, as in the case we describe. Auditory evoked potentials likewise confirm their diagnostic value with regard both to the site of the lesion and to its dorsal extent toward the pontine tegmentum.

Osmotic demyelination syndrome following correction of hyponatremia

The treatment of hyponatremia is controversial: some authorities have cautioned that rapid correction causes central pontine myelinolysis, and others warn that severe hyponatremia has a high mortality rate unless it is corrected rapidly. Eight patients treated over a five-year period at our two institutions had a neurologic syndrome with clinical or pathological findings typical of central pontine myelinolysis, which developed after the patients presented with severe hyponatremia. Each patient's condition worsened after relatively rapid correction of hyponatremia (greater than 12 mmol of sodium per liter per day)--a phenomenon that we have called the osmotic demyelination syndrome. Five of the patients were treated at one hospital, and accounted for all the neurologic complications recorded among 60 patients with serum sodium concentrations below 116 mmol per liter; no patient in whom the sodium level was raised by less than 12 mmol per liter per day had any neurologic sequelae. Reviewing published reports on patients with very severe hyponatremia (serum sodium less than 106 mmol per liter) revealed that neurologic sequelae were associated with correction of hyponatremia by more than 12 mmol per liter per day; when correction proceeded more slowly, patients had uneventful recoveries. We suggest that the osmotic demyelination syndrome is a preventable complication of overly rapid correction of chronic hyponatremia.

Mild central pontine myelinolysis: a frequently undetected syndrome

Over a period of 1 year we diagnosed central pontine myelinolysis (CPM) in five patients all of whom survived, two of them with complete functional recovery despite extensive lesions on cranial computerized tomography and magnetic resonance imaging. Diagnosis was based upon the combination of an acute brainstem dysfunction with typical neuroradiological features; a history of chronic alcoholism or a preceding hyponatremia may serve as a diagnostic hint. The spectrum of symptoms ranged from severe tetraplegia and cranial nerve palsies to latent signs of pyramidal tract lesions and discrete ocular motor abnormalities. In two patients pontine and extrapontine manifestations of demyelination were confirmed neuroradiologically; in one patient a solely extrapontine manifestation was present. Thus it is reasonable that: (1) the incidence of comparatively mild forms of CPM as well as extrapontine manifestations are more frequent than hitherto assumed, (2) the clinical outcome of the syndrome is better than expected from earlier fatal case reports and is quite independent of the extent of the lesion as it appears with brain imaging methods.

Changing concepts in treatment of severe symptomatic hyponatremia. Rapid correction and possible relation to central pontine myelinolysis

Severe symptomatic hyponatremia (serum sodium level below 120 meq/liter) is often a life-threatening emergency that can result in permanent neurologic damage or death if left untreated. Early recognition and rapid correction to mildly hyponatremic levels by the administration of hypertonic saline are important in order to reduce the potential mortality and morbidity. If the serum sodium level is more than 105 meq/liter, it can be corrected to a value of 125 to 130 meq/liter. However, if the serum sodium level is less than 105 meq/liter, it may be safe to raise the value by only 20 meq/liter. Care should be taken to avoid acute correction to normonatremia or hypernatremia. Moreover, it is also of equal importance to avoid development of hypernatremia in the subsequent days following the correction to mild hyponatremia.

Brachial diplegia in central pontine myelinolysis

A patient developed weakness in the upper limbs, eventually causing brachial diplegia with only slight paresis of the legs after rapid correction of severe hyponatraemia. Pseudobulbar palsy, mental confusion and urinary incontinence were also present. CT scan showed a zone of lucency in the pons. Clinical recovery occurred and the zone of lucency had disappeared 12 months after the appearance of the neurological signs.

Clinical and CT confirmed recovery from central pontine myelinolysis

The clinical and CT features of a young alcoholic man, suffering from central pontine myelinolysis with clinical improvement and partial resolution of the lesion, documented by high resolution scan 2 years later, are reported.

Association between rise in serum sodium and central pontine myelinolysis

Twelve hyponatremic patients with central pontine myelinolysis (CPM) showed a rise in serum sodium levels 3 to 10 days (mean, 6) prior to the development of CPM. The increase exceeded 20 mEq/L within 1 to 3 days and was then sustained for an additional 3 to 5 days. In addition, 11 of the 12 CPM patients achieved a sodium value of 147 mEq/L or greater during the period of sodium elevation. The rise in sodium frequently coincided with administration of saline solutions, diuretics, steroids, and lactulose. In contrast, 9 hyponatremic patients who did not have CPM showed sodium increases that were significantly less or slower (or both) following treatment of hyponatremia. Our findings suggest that CPM may be caused by a too rapid or excessive rise in serum sodium from a hyponatremic baseline.

Central pontine myelinolysis in association with Hodgkin's lymphoma

Central pontine myelinolysis was found histologically in a young man who died with Hodgkin's lymphoma. Clinically he had developed a progressive peripheral sensory deficit, ataxia, quadriparesis, dysarthria, incontinence and drowsiness. This is the fifth case reported in the British literature. The pathogenesis and aetiology of this primary demyelinating disease are considered.

Visual and auditory evoked potentials in a case of Marchiafava Bignami Disease

Brainstem auditory evoked potentials and visual evoked potentials to both flash and pattern reversal stimulation were recorded in a case of clinically diagnosed Marchiafava Bignami Disease (M.B.D.) A CT scan revealed dilation of the supratentorial ventricular system and fairly extensive cortical atrophy. The brainstem potentials showed a non-specific abnormality of the N4 component, (in the region of the caudal pons) and were inconclusive. The visual evoked potentials to flash stimulation were delayed while pattern reversal responses were within normal limits.

Auditory evoked responses and computerized tomography in central pontine myelinolysis

We present the first case of central pontine myelinolysis (CPM) confirmed by high resolution computerized tomography (CT) in which auditory brainstem responses (ABR) revealed impaired conduction beyond the mid pons. The combined use of CT and ABR in the diagnosis of central pontine myelinolysis is discussed.